Master stripping means for rotary printing machines



July 2, 1963' HP. GAMMETER ETAL 3,095,809

MASTER STRIPPING MEANS FOR ROTARY PRINTING MACHINES Filed Sept. 26, 19607 Sheets-Sheet 1 Fl (3 l //A as INVENTORS.

HARRY F. GAMMETER FRANCIS R. PATALON BY RUDOLPH J. KATTERLE ATTORNEYSJuly 2, 1963 H. F. GAMMETER ETAL 3,095,809

MASTER STRIPPING MEANS FOR ROTARY PRINTING MACHINES 7 Sheets-Sheet 2Filed Sept. 26, 1960 INVENTORS. HARRY F. GAMMETER FRANCIS R.PATALONmw7J4 M/M ATTORNEYS RUDOLPH J. KATTERLE July 2, 1963 H. F. GAMMETER ETALMASTER STRIPPING MEANS FOR ROTARY PRINTING MACHINES Filed Sept. 26, 19607 Sheets-Sheet 5 INVENTORS. HARRY F. GAMMETER FRANCiS R. PATALON BYRUDOLPH J. KATTERLE m/fim/ TO R N EYS y 1963 H. F. GAMMETER ETAL 3,

MASTER STRIPPING MEANS FOR ROTARY PRINTING MACHINES 7 Sheets-Sheet 4Filed Sept. 26, 1960 INVENTORS. HARRY F. GAMMETER FRANCIS R. PATALON swm. N- .1

BY RUDOLPH J KATTlERiE ATTORNEYS July 2, 1963 H. F. GAMMETER ETAL 3,0

MASTER STRIPPING MEANS FOR ROTARY PRINTING MACHINES 7 Sheets-Sheet 5Filed Sept. 26, 1960 HARRY F. GAMMETER 5555? QTE E QL RNEYS INVENTORS.

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MASTER STRIPPING MEANS FOR ROTARY PRINTING MACHINES Filed Sept. 26, 19607 Sheets-Sheet 6 HARRY F. MMETER FR CIS R. PATALON W RU LPH J. KAT'IZRLEZ d' \7/ 0;7 M M iATT ORNEYS July 2, 1963 H. F. GAMMETER ETAL 3,

MASTER STRIPPING MEANS FOR ROTARY PRINTING MACHINES '7 Sheets-Sheet 7Filed Sept. 26, 1960 FRAN ll BY RUDOLPH J TTERLE INVENTORS. GAMMETER R.PATALON ATTORNEYS HARR United States Patent 3,095,809 MASTER STRIPPINGMEANS FOR ROTARY PRINTING MACHINES Harry F. Gammeter, Cleveland Heights,Francis R. Patalon, Willowick, and Rudolph J. Katterle, East Cleveland,Ohio, assignors to Addressograph-lvlultigraph Corporation, Cleveland,Ohio, a corporation of Delaware Filed Sept. 26, 1960, Ser. No. 58,399 8Claims. (Cl. 191-217) This invention relates to a rotary oif-setprinting machine.

In a rotary off-set printing machine, that is, one operating on thelithographic principle, a master plate is prepared bearing an inkreceptive form of the image to be .duplicated, and this master isclamped in place on the so-called master or printing cylinder. The imageis selectively faced with ink on the basis of the lithographicprinciple, and the ink is oil-set in reverse image form on to thereceptive surface of a so-called blanket on a blanket cylinder. Theblanket cylinder is coupled with 'an impression cylinder, and the sheetsto be printed are fed between the blanket and the impression cylinder toreceive the image in direct reading form from the blanket in successivecycles of the machine.

It is advantageous to be able to run the machine under circumstanceswhere the master will be automatically removed or stripped from themaster cylinder, after a predetermined number of machine cycles, byopening the clamps which hold the master in place. This is especially soin those instances where it is desired to use a particular master for nomore than the recommended or desired number of impressions, and theprimary object of the present invention is to enable this to beaccomplished in a rotary off-set printing machine by parts that can beeasily arranged in virtually any given machine of this class wherein thecylinders referred to are disposed between supporting side plates.Specifically, it is an object of the present invention to open themaster clamp by actuating a cam that is conveniently located adjacentthe inside face of a side plate ot-the machine, and to actuate the camby a train of links including a releasing latch that are substantiallyin the plane of the cam. The releasing latch is under control of asolenoid or equivalent element that is to be energized after thepredetermined number of machine cycles or impressions has been attained.

Another object of the present invention is to so associa-te stripperelements with the master clamp releasing cam that these will be activeonly at the time the cam is actuated and as an incident thereto to peelthe released master from the master cylinder. Objects of the inventionrelated to this are to actively pull the stripped master away from themaster cylinder in an ejector operation and into a collecting tray, andtodo this in such a way that the master will not be damaged to theextent that it cannot be reused; and to so construct and arrange therelated ejector mechanism as to be removably mounted as a separateejector attachment or unit on virtually any given machine of theaforesaid character.

Other objects of the present invention are to accurately control theaction of the clamp releasing cam and the stripper elements; toaccurately guide the stripped master to the ejector mechanism so thatthere is assurance that the master being ejected will not become jammedin the machine; to assure a firm and positive ejecting action on theused master; and to accurately time and control the operation of thestripper elements.

Other and further objects of the present invention will be apparent fromthe following description and claims and are illustrated in theaccompanying drawings which,

ice

by way of illustration, show the preferred embodiment of the presentinvention and the principle thereof and what is now considered to be thebest mode contemplated for applying that principle. Other embodiments ofthe invention embodying the same or equivalent principles may be usedand structural changes may be made as desired by' those skilled in theart without departing from the present invention.

In the drawings:

FIG. 1 is a perspective view from the top front of a machine constructedin accordance with the present invention and wherein the master andblanket cylinders have been removed;

FIG. 2 is a perspective view at the bottom rear of the machine;

FIG. 3 is a side elevation of the machine;

FIG. 4 is a side sectional view of the machine taken on the line l4 ofFIG. 5;

FIG. 5 is a top plan view of the machine taken on the line 5-5 of FIG.3;

FIG. 6 is a sectional view on an enlarged scale taken substantially onthe line 6-6 of FIG. 5;

FIG. 7 is a detail plan view ofthe shaft in the machine which supportsthe stripper fingers;

FIG. 7A is a fragmentary sectional view of an end portion of the shaftshown in FIG. 7; and

FIGS. 8 and 9 are sectional views, each on an enlarged scale, and takenon the lines 8-8 and 99 of FIG. 5.

As introductory to the arrangement of parts in the machine of thisinvention, attention is directed first to FIGS. 1, 4 and 5 which bestshow that a master cylinder 10, on which the duplicating lithographicmaster is mounted, is arranged on a shaft 10A for rotation between apair of sturdy rear side plates ll and 12. These plates are part of themain frame of the machine which also includes a pair of forward sideplates 11A and 12A. The plates 11 and 12 are pivotally mounted on ashafit 13, FIG. 4, supported by the front side plates 11A and 12A, andthe frame plates are rigidly interconnected by various tie bars TB aswill be evident in FIG. 4.

The master or plate cylinder 10 is gear driven and is arranged to rotatein contact with a blanket cylinder 14 which is supported on a shaft 14Ain turn supported by the side plates 11A and 12A. The lblanket cylinderis located above an impression cylinder 15 and defines a lbighttherewith as will be evident in FIG. 4. The impression cylinder includesa shaft 15A supported for rotation between the side plates 11A and 12A.The image on the master plate carried on cylinder 16' is inked, and theink representations are transferred to the blanket cylinder and in turnare transferred thence to the sheet to be printed that is fed betweenthe blanket and the impression cylinder.

The clamping mechanism with which the present invention is particularlyconcerned is mounted in an axially extending gap or recess formed in theperiphery of the master cylinder -10, FIG. 6. This mechanism isdescribed in more detail in Patent No. 2,813,482 and ineludes anelongated channel-like flange and support 21 of U-shape, the web ofwhich is secured by bolts to one wall 23 of the gap in the mastercylinder. The upper one of the flanges or legs 25 of the support 21extends axially of the cylinder and lies a short distance below theperiphery thereof, and resultantly forms an anvil against which one endof a master printing plate or sheet may be clamped. A plurality ofplungers or pins 26 are mounted in spaced openings formed in the flange25 for reciprocation in a direction normal to the flanges.

A thin disc-like clamping member 30 is secured to the upper end of eachplunger :or pin 26, FIGS. 5 and 6. These clamping members lie above theupper flange 25 and are aligned in a row which extends axially of the 3drum. The clamping members 39 are individually biased toward theaforesaid anvil by springs 31, FIG. 6, which encircle the respectivepins 26 and are interposed between the upper flange 25 of the supportand respective split retaining rings mounted in annular recesses formedin the pins 26.

When one end of a thin, flexible lithographic printing plate ispositioned between the clamping members or discs 30 and the anvil, withits adjacent edge abutting the pins 26, the force of the springs 31 issufficient to retain the end of the printing plate firmly affixed to themaster cylinder. However, such retaining force may be supplemented bythe engagement of the plate by a series of relatively small sharpmetallic spurs 32 carried by a plate 32F which is interposed between thesupport 21 and the wall 23. One such spur extends upward adjacent eachclamping disc 30 so that a master sheet or plate will be forced by thediscs 30 into engagement with the spurs. The opposite or trailing end ofthe printing plate may be unsecured.

The present invention is particularly concerned with the clampingmembers 36 for the leading end of the printing plate and the mechanismfor operating the same. The clamping members 31), heretofore described,are moved to their sheet receiving or releasing position, by a commonoperating rod or bar 49 which bears on lower extensions of the plungers26, FIG. 6, and this bar is actuated by a cam as will be described indetail.

Thus, the rod 40 extends axially of the master cylinder within the gapand underlies the inner or lower ends of the plungers 26. The ends ofthe rod 40 are mounted in respective brackets 41 which are pivotallymounted on a shaft 42 rotatably journaled in the end plates of themaster cylinder. A pair of arms 43 is secured to the shaft 42 within thegap of the master cylinder and adjacent respective brackets 41 so as tomove with the shaft when the latter is rocked in a manner to beexplained.

The arms 43 are adapted to transmit counterclockwise movement of theshaft 42, as viewed in EEG. 6, to the brackets 41 and also retain thebrackets in position axially on such shaft. To this end, each bracket 41has an inturned lip 41L which overlies its respective arm 43 and carriesan adjusting screw 415 which engages such arm to transmitcounterclockwise movement of the shaft 42 to the brackets 41.

Each bracket 41 carries a pin 41F, FIGS. and 6, which extends freelythrough an enlarged opening 43A in its respective arm 43. An enlargedwasher is provided on the outer end of each such pin, and a plurality ofdiscs 45 encircle the pin 411 between the Washer and the related arm 43.At least one of these discs comprises a spring-like member which exertsan axial pressure on the arm 43 to thereby frictionally clutch the armand bracket together for movement as a unit about the axis of the shaft42, and yet permit adjustment of the position of the arm relative to thebracket by the adjusting screw 418.

A cam plate 46, FIGS. 1 and 4, which is one element for controlling theposition of the clamping members 30 by actuation of the shaft 42 isfixed to the inside face of the frame member 11 of the printing machine.This cam is positioned in the path of a pawl 47 pivotally mounted as at48 on an arm 42A secured to one end of the shaft 42 which extendsaxially beyond the end of the cylinder which lies adjacent the cam 46. Aspring 478 normally holds the pawl 47 against a stop 42X carried by thearm 42A. When the cylinder 10 is rotated in a counterclockwise orprinting direction, as viewed in FIG. 4, the pawl 47 engages the can 46and is freely rocked about its pivot without any effect. Thus, duringrotation of the printing cylinder in a printing direction cam 46 has noeffect upon the master sheet clamping mechanism.

On the other hand, rotation of the master cylinder in a clockwise ornon-printing direction from the position indicated in FIG. 4 produces apositive engagement between the free end of pawl 47 and any one ofseveral stepped cam surfaces 46A, FIG. 4, afforded by the cam plate 46,and all of the clamping members 30 are shifted to their open position torelease or receive a master sheet. Such rotation can be effectedmanually, and tends to swing the pawl 47 counterclockwise about itspivot 48, but this movement is restrain-ed by the stop pin 46, and theresult is a counterclockwise movement of the pawl carrying arm 42A, theshaft 42 to which it is secured, the arm 43, and the brackets 41. Thismovement of the brackets 41 causes the rod 4%), carried thereby, to liftthe pins 26, raising their respective clamping members 30 out of contactwith the anvil 25. In this position a previously clamped sheet isreleased for manual removal, and the clamping members 3t? are inposition to receive another master sheet.

To position a master sheet, the master cylinder 10 is positioned asabove described to open the clamps 30. One end of a master sheet isplaced on the anvil surface 25 with the adjacent edge thereof abuttingthe plungers 26 and the left band edge engaging a side guide asdescribed in Patent No. 2,813,482. This positions the master bothcircumferentially and axially relative to the cylinder. The operatorholds the sheet in such position and slowly rotates the cylinder to movethe rod 40 away from the plungers 26 and permit the spring 31 to drawthe clamping members 30 toward the anvil 25 and clamp the sheetpositioned therebetween. The latter movement of the cylinder may be ineither direction, although the construction is such that it is moreconvenient to use a counterclockwise or printing movement. In eithercase the pawl 47 quickly disengages the cam 46 and the parts return totheir normal positions. Cam 46, it will be noted, includes a pluralityof cam rises as 46A, and the reason for this is explained in Patent No.2,813,482.

Under and in accordance with the present invention release of the clamps30* is effected by means operable automatically after a predeterminednumber of prints or machine cycles. This is accomplished by providingarm 42A with a cam follower 66, FIG. 4, which is adapted to engagemaster clamp releasing means in the form of a rise R, FIG. 4, on a cam70 when the rise 70R is in the dotted line position indicated in FIG. 4which rep resents the position to which the cam .70 is moved or releasedafter completion of the predetermined number of machine cycles, as willbe described in detail below. Cam 70 is pivotally located at the insideface of the frame plate 11 as shown in FIG. 1 and is in a predeterminedplane. Cam 7i) is under control of a latch 73, FIGS. 1 and 4,substantially in the plane aforesaid. Latch 73 is normally unreleased,but the latch 73 in turn is under control of an arm 75 which'is locatedat the inside of frame plate 11A. Arm 75 is connected to the armature ofa solenoid (not shown) which is associated with a counting mechanismwhich constitutes no part of the present invention.

The cam 70 is spring-biased to its normal or ineffective position shownin FIG. 4 as will be described in more detail hereinafter, andintermediate links are interposed between the cam 70 and the latch 73substantially in the plane thereof in such a manner that the cam 70 willbe forced to its dotted line position shown in FIG. 4 when thepredetermined number of counts has been registered by the countingmechanism. Thus, the latch and cam parts and connecting links whichcontrol automatic master plate release can be conveniently locatedinside a frame of an existing machine, such as that disclosed in theaforesaid patent, without any significant alterations.

The count controlled arm 75 is generally vertically extended and isformed with a flange 75A, FIG. 4, at the upper end thereof. The flange75A bears against a downwardly directed projection 73 formed on thereleasing latch 73, and this condition is in part maintained by a spring77 which is anchored at the lower end on a pin 75P fixed adjacent thelower end of the arm 75, and the upper end of the spring 77 is anchoredon a pin 79 which is afiixed to the inside face of the frame plate 11Aof the machine adjacent which the arm 75 is located.

Latch 73 is pivotally mounted on a supporting stud 81, FIGS. 1 and 4,which is atiixed to the inside face of frame plate 11A of the machine,and a spring 82, anchored at its lower end to a frame plate mounting pin83 and anchored at its upper end to a pin 84 on the latch 73, iseffective to bias the latch 73 downwardly as viewed in FIG. 4 so thatfirm contact is established between the latch projection 73F and theflange 75A of arm 75.

As will be evident in FIG. 4, the latch 73 is generally crescent-shaped,and the pivot 81 is located near one end of the crescent. The oppositeend of the crescent-shaped latch 73 is formed with a notch '73N in whichis normally located one corner of a lug 85E provided at the lower end ofa relatively large bell crank 85. This bell crank is carried on a shaft86 which projects inward from the adjacent side plate 11A of themachine. Shaft 86 is arranged for limited rocking movement, for apurpose to be explained, when the latch 73 is released. The bell crankis substantially in the plane of the cam 70, and the arm of the bellcrank 85 opposite the arm which carries the projection 85B is providedwith a pin 88. The upper end of a spring 911 is :aflixed to the pin 88,and the lower end of spring 90 is anchored on a pin 91 which projectsinward from the side plate 11A of the machine which supports the stud 85representing the fulcrum of the bell crank 85. Thus, the spring 91 iseffective normally to bias the bell crank 85 in a counterclockwisedirection as viewed in FIG. 4.

The latch 73 and the bell crank 85, it will be appreciated, aresubstantially in the same plane, and this plane is also occupied by arelatively small bell crank 92 which serves as an intermediate linkbetween the count controlled latch mechanism and the releasing cam 70.Thus, as shown in FIGS. 1 and 4, the bell crank 92 is free to swing on apivot stud 93 which is supported by the frame plate which supports theelements 81 and as. The bell cranks are interconnected pivotally by alink plate 95 Winch is pivotally connected at the opposite ends thereofto the adjacent ends of the bell cranks 85 and 92 respectively by pins96 and 97. The end cf the bell crank 92 which is adjacent the end 79E ofthe clamp releasing cam 7 is extended thereunder to engage and lift thiscam.

The releasing cam 70 is in the form of a relatively long arm as will beapparent from FIG. 4 and is pivoted, in- .termediate its ends, on a stud105 which projects inwardly from the side plate 1J1 of the machine.Thus, the cam arm 71) projects quite far to the left of the pivot 105 aswill be apparent in FIG. 4 and is provided with a pin 166 at the lefthand end 7 9L thereof. One end of a spring 110 is anchored to this pin,and the opposite or upper end of the spring 111 is anchored on a lug112L that is bent inwardly from one end of a plate :112 which issupported at the inside face of frame plate 11. The plate 112 isprovided with a guide arm 113, FIG. 4, which serves as a guiding supportfor cam 79.

Finally, in connection with control over cam 70, it should be noted thatthe shaft 86, which carries the bell crank 85 projects outward of theadjacent frame plate .as shown in FIG. and an arm 1 15 is afiixedthereto at one end. The opposite end of arm 115 is provided with afollower 115 which is disposed in the path of a cam 117, FIG. 3, thatrotates with the blanket cylinder. The cam is adjustable through asupporting eccentric b ushing 118, FIG. 3, and in each cycle of themachine the rise 117R of cam 117 nudges the follower 116. It will alsobe noted, FIG. 4, that the bell crank 85 is secured to shaft 86 by aclamp 120. The clamp plate 121 bears against the flat bottom of a notchin shaft 86 and the bell crank 85 at its 6 mid-section has acrescent-shaped notch that embraces the lower half of shaft 86. IBolts121 secure the bell crank to the clamp and join both tightly to theshaft 86, and these bolts permit the bell crank to be rotatably.adjusted relative to shaft 86.

When the counting solenoid energizes, it exerts a downward pull on arm75, and the latch 73 is released from the extension E of the rocker armor bell crank. When the cam rise 117R passes off follower 116 on arm115, the bell crank 85 is then free to pivot counterclockwise as viewedin FIG. 4 to the extent permitted by its control cam 117, and thismotion is transmitted through links 92 and to the clamp releasing cam70' causing the latter to be moved to its active position indicated bythe dotted lines in FIG. 4. This action takes place against theresistance of spring 110. The rise 70R is, therefore, disposed in thepath of the clamp release follower 60, FIG. 4, and when this followerengages the rise 70R, the clamps 30 are opened as an incident to rockingof shaft 42, thereby releasing the leading edge of the plate on themaster cylinder. The master thus released is stripped from the mastercylinder and is guided and ejected into a receiving tray 120, FIG. 4, ina manner now to be described.

The master is stripped and initially guided away from the mastercylinder toward the tray by three uniformly spaced stripper fingers 130,FIGS. 4, 8 and 9 which are in the form of relatively narrow blades.These fingers are normally held spaced away from the surface of themaster cylinder in a non-stripping or retracted position as will bedescribed below. Each is provided with an arcuate forward edge A whichis curved complemental to the radius of curvature of the mastercylinder. Each stripper finger includes an arcuate guide surcface 13113at the back thereof which serves to guide the stripped master in thedirection of the receiving tray, and the two surfaces 130A and 13GBmerge into a relatively narrow point 131W which serves to afford theprimary stripping action.

The stripper fingers 1311 are arranged in spaced relation on a supportshaft 132 which extends between frame plates 11 and 12, and in thisconnection it should be pointed out that these frame plates at the leftand right sides of the machine serve as mountings for the mastercylinder bearings, other supporting members, the stub 1115 on which thereleasing clamp 71 is pivoted and other parts hereinafter described.

As was mentioned, the stripper fingers 1311 are carried on a supportingshaft 132, and to this end each stripper blade at the lower edge thereofis formed with a half round opening 135, FIG. 8. This opening is shapedcomplemental to a corresponding groove 132G, FIGS. 7 and 7A, formed atan appropriate location along the length of stripper fingers supportingshaft 132. The stripper shaft 132 is formed with flat sunfaces 132F atthe location of each groove 1326 and on the side thereof opposite thegroove. Each such flat surface is shaped to receive a correspondingprojection A, FIG. 8, provided on a retainer plate 140. Thus, there is aretainer plate :140 for each stripper finger 130, and each stripperfinger is provided with a pair of studs 142, FIG. 8, having threadedportions of reduced diameter adapted to project through correspondingopenings in the related clamp plate 140. Nuts 140N, FIG. 8, are threadedon to the projecting ends of the studs 142, and these enable the fiatface of the projection 140A of the clamp 140 to be drawn tight againstthe flat surface 13'2F on the stripper shaft and thereby adjustablysecure each stripper to the support shaft 132.

[As shown in FIG. 7lA, each end of the stripper shaft is recessed inwardfor a substantial distance, and a coil spring 146 is mounted in aninnermost pocket 147 of the stripper shaft, this pocket being ofsufiicient depth and of reduced diameter to serve as a guide for therelated spring 146. A plunger 148 is. disposed at the outermost end ofthe recess at each end of the stripper support shaft 132, and its freeouter end is formed with stud 1 53A which projects outwardly beyond therelated terminal end of the stripper shaft 132. One end of the coilspring 146 bears against the opposite end 1483 of the plunger 148 toexert an outwardly directed force on the plunger 148.

Each plunger 148 is provided :with a pin which is disposed in a slot 151at the end of the stripper shaft 13?. The plunger is first disposed inthe pocket at the end of the stripper shaft, and thereafter the pin 159is press fitted in place to serve as a stop limiting the extent to whichthe spring 146 presses the plunger 143 outwardly.

The projecting studs 148A of each plunger are adapted to fit insupporting elements that are provided on the inside faces of the frameplates 11 and 12.

[1 he stripper shaft 132 is in the nature of a rock shaft and is socontrolled that the stripper fingers 13% are moved into strippingposition when the releasing earn 7 has been shifted to its activeposition. However, so long as the clamp releasing cam is inactive, meansare effective to hold the stripper fingers away from the mastercylinder. To this end, the stripper shaft has a bell crank 16%), FIGS. 6and 7, aflixed to one end thereof. Gne arm 160A thereof is connected tothe lower end of a spring 161 which has the upper end anchored to a pin162 provided on a mounting plate 163 which in turn is secured to theinside face of the frame plate 12 at the side of the rn-a chine oppositethe, clamp releasing cam 79.

The other arm 16GB of the bell crank 16% carries a follower roller 170,and this follower is disposed immediately opposite a stripper fingercontrol cam 171, FIGS. 5 and 6. This cam is in the form of a relativelylarge disc having a diameter slightly smaller than the master cylinderand is fixed to the master cylinder shaft to rotate therewith at the endof the master cylinder opposite the cam as shown in FIG. 5. The cam 171is formed with a depression 171D, FIG. 6, and the relationship is suchthat when the follower 1'70 is free to move into the depression 171D,this is accompanied by clockwise motion of the shaft 132, FIG. 6, andinward movement of the stripper fingers toward the master cylinder for atime duration sufiicient to enable the stripper fingers to strip thereleased master from the master cylinder. This is but a small portion ofthe 360 cycle of cam 171 as will be evident from the configuration ofcam 171 shown in FIG. 5, such that the stripper fingers are inward for abrief time only and are thereafter moved in a return direction once thecam depression 171D has been moved past the follower 170.

The bell crank and its follower are normally held in an inactive orretracted position, and this is achieved by relating the action of thebell crank 168 to the action of the clamp releasing cam 70. Thus, arelease element in the form of an arm 175, FIGS. 6 and 7, is aflixed tothe end of the tripper shaft 132 opposite the bell crank 160 so as tolie adjacent cam 76. The release arm is provided with a rearwardlyextending flange 176, and a stud 177, which has an end projecting freeof the flange 176, is anchored therein.

The stud 177, as shown in FIGS. 3 and 4, is normally engaged by the toe178 of a releasable stop which is freely pivoted on the end of thestripper shaft 132 on which the release arm 175 is aflixed, and it willbe recognized that the spring 161, FIG. 6, is effective to hold the stud177 against the opposed part 178 of the stop 180. Stop 180 is providedwith a pin 182, HG. 4, which is so located as to engage a shoulder 70Aadjacent the rear portion of the clamp releasing cam 70*, and in thismanner the clamp releasing cam 70 in its ineffective position serves thefunction of holding the stripper fingers in an inactive position.

However, when the cam 70 moves to its active position, shoulder 70Athereof is lowered as viewed in FIG. 4. Consequently, the stop 180 isreleased and is not effective to prevent the stripper shaft follower 170from following the contour of the stripper shaft control cam 171.Therefore, when cam 76 is released, conditions are established as anincident thereto which enable the stripper fingers 130 to be effective.

When the master clamps 34 are released, the stripper fingers 131} areeffective on the leading edge of the master at a point somewhat belowthe bight between the surface of the master cylinder and the surface ofa lower ink form roller 1%, FIG. 3, and during the course of initialstripping, the released master travels along the arcuate guide surfaces136d? of the stripper fingers. In this connection, it is to be pointedout that the flange 25, FIG. 6, is notched at three intervals 25G, FIG.5, inward from the leading edge, and this enable the stripper fingers130, in effect to get under the leading edge of the released master.Additionally, the radial wall 23, FIG. 6, of the master cylinder justrearward of the flange 25 is sloped at 238 so that the stripper fingerswill not jam against the master cylinder during stripping action. Asmentioned above, the stripped master is to be accurately guided into areceiving tray, and this action occurs at a point below the lower inkform roller which is frictionally driven. At this time, roller 190 and alike upper roller 1% are moved slightly away from the master cylinder,as will be explained, and feed means are effective in order to. pull thestripped master away from the master cylinder. In accomplishing this, anauxiliary stripper and ejector unit 260, FIGS. 2 to 4, is removablymounted in the machine and is supported primarily by the side plates 11and 12.

Thus, a pair of mounting brackets as 291, FIG. 3, are secured to thelower edges of the auxiliary side plates as Hand 12. The separableattachment 2% is constructed to include a pair of side platesas 203 and204, FIGS. 3 and 4, and these are rigidly connected by a pair oftransverse tie bars 2% and 267, FIG. 4. Each of the side plates 293 and204 includes lower edges 208 that are disposed below the lower edges ofthe side plates 11 and 12 of the machine as will be evident in FIGS. 3and 4, and each such side plates 203 and 204 includes upper surfaces 216which, when the unit 200 is mounted in the machine, extend upwardbetween the side plates 11 and 12.

In releasably connecting the ejecting unit 230 to the machine, resort isbad to a pair of manually operable latch elements in the form of pawls215. Each pawl 215 fits in a groove at the forward end of the relatedplate 2%1 and is pivotally supported therein by a pin 216, FIG. 3 in therelated groove. Each pawl 215 includes a toe 215T which extends rearwardof the pivot 216, and each pawl 215 is notched at 215N, FIG. 3. The toe215T of each pawl is en-gageable with a spring detent in the form of aspring-biased ball 218, FIG. 3, which is mounted in a recess alignedwith the groove in which the pawl 215 is disposed. Thus, the springdetents are effective to supply a clockwise force to each pawl 215 asviewed in FIG. 3, and the notches 21SN are so located as to embrace astud 2W5, FIG. 2, afiorded at each end of the transverse tie bar 297which serves in part to rigidly connect the side plates 263 and 204.

It will also be noted that each mounting bar or plate as 29 1 is formedwith a slot 22%, FIGS. 1 and 3, at the rear edge thereof, and theseslots are so located as to embrace studs 2865 at the ends of the tie bar266. Thus, in disposing the unit 20 in the machine, the studs on the tiebar 2% are first aligned with the notches 221 and are fitted therein.The unit 2% is then pivoted upwardly to cause the studs on the tie bar267 to bear against the sloped or cammed edges 222 at the rear edges ofthe pawls 215, pivoting the pawls counterclockwise as viewed in FIGS. 3,and motion is continued until the tie bar studs 21978 are disposed innotched corners LES-1N, FIG. 3, at the forward edges of the mountingplates as 201.

r The pawls 215 then spring back and have the shoulder 9 elements of thenotches 215N thereof effectively engaged with the complemental studparts of the tie bar 207 to hold the ejector unit 200 in place.

The unit 200 supports a plurality of guide elements that are associatedwith the stripper fingers so as to assure proper guiding relation of themaster strip that is being removed from the master cylinder. Theseguides include fingers 230, 'FIG. 4, which have lower arcuate surfaces230A that are shaped complemental to the curved backs of the stripperfingers, and these guide surfaces are spaced slightly from one anotheras shown in FIG. 4 to define a guide throat through which passes themaster being stripped.

As shown in FIG. 5, seven such guide members 230 are provided and eachis formed at the top edge thereof with a circular notch 230N adapted tofit in a related groove 2316, FIG. 8, formed in the guide finger supportshaft 231. Shaft 231, it will be noted in FIG. 5, is sup ported at theopposite ends thereof in the side plates 203 and 204.

Each guide finger 230 is formed with an enlarged opening 233intermediate the edges thereof, and this opening communicates with anopening 234 somewhat smaller in diameter. The opening 234 of smallerdiameter is proportioned to neatly fit in a groove in a shaft 235arranged parallel to and somewhat below the shaft 231 in the unit 200,and the opening 233 is proportioned to enable shaft 235 to be insertedtherethrough. After such insertion, the fingers 230 are shifted toproduce a complemental fit between the edges of the openings 234 and theaforesaid grooves in shaft 235. This assembly is then supported on shaft231 by a pair of spring clips 240, FIGS. 5, 8 and 9, each having anupper bight 240A adapted to fit in a related relatively wide notch inshaft 231 as will be evident in FIG. 5. Each clip 240 is formed with alower bight 240B adapted to fit in a like notch in shaft 235. The partsare so dimensioned that the lower arcuate faces of the fingers 230 willbe spaced slightly from the upper face of a lower guide plate 245 todefine therewith a narrow passageway into which the stripped master isadvanced.

Thus, a plate 245 of sheet metal is disposed below the lower curvededges of the guide fingers 230 as will be evident in FIG. 8, and thisguide is so positioned and related as to cooperate with the fingers 230in directing the stripped master into the bight of related ejector feedrollers 246 and 247 which are rearward of the guides 230. The guideplate 245 is a removable element and has a rear portion thereof formedwith a plurality of notches 245N as shown in FIG. 5. These notchesembrace the rollers 247, and the solid or unnotched portions at the rearmargin of the guide plate 245 overlie a shaft 248 which serves tosupport and drive the rollers 247 in a manner to be explained. The guideplate 245 extends forwardly therefrom in an upwardly bent direction, andthis relationship is maintained by disposing the forward edge portion ofthe guide plate 245 between pairs of slightly spaced studs 250 and 251,FIGS. and 8, these studs being afiixed to the inside faces of the plates203' and 204. It will also be noted from FIG. 5 that the forward edge ofthe guide plate 245 is notched at 253 to enable the rear edges of thestripper fingers 130 to be freely active. The guide plate 245 is socurved as to point the master being stripped into the bight of therelated rollers 246 and 247 as was mentioned above. There are threerollers 246 as will be noted in FIG. 5, and these are of large diameterand have relatively narrow rims, and each is a steel roller formed witha boss 246B secured by a set screw to a supporting shaft 255 which isgear driven as will be explained. The related rollers 247 are rubberrollers, and three of these 247A, 247B, and 2470, FIG. 5, are directlyopposite and engaged with related ones of the three steel rollers 246.Additional ones of the rollers 247 are arranged between these threerollers 246.

The shaft 248 which carries the rubber rollers 247 is provided at theends thereof with hearing supports 260, FIGS. 2 and 3, which have flatsurfaces adapted to fit in slots 203$ formed in the side plates 203' and204. Relatively strong leaf springs as 261 are tensioned between a pairof studs 264 and 265 on each side plate as 203, and the forward end ofeach such spring is pressed downwardly to underlie and engage eachbearing support as 260 to thereby apply a spring retaining force to theshaft 248 which supports the rollers 247.

Shaft 248 is provided with a gear 248G, FIGS. 2 and 4, which is drivenby a gear 255G which is carried by shaft 255. Gear 255G is located atoneend of shaft 255. A smaller gear 270, FIGS. 2 and 3, is secured to shaft255 at the other end thereof, and this gear is meshed with an idler gear271 which is in turn driven by a constantly rotating gear 273, FIG. 3.

Thus, it will be seen that the rollers 246 and 247 serve to impart awithdrawing action to a stripped master, and this master is ejected bysuch rollers into the inclined receiving tray which is supported by theauxiliary or ejector unit 200. The shaft 248 can be readily removed toenable the rollers 246 and 247 to be cleaned.

It will be seen from the foregoing that under the present invention, aused master is released and stripped automatically from the supportingcylinder in a cyclically operable off-set printing machine. This can beaccomplished automatically as an incident to the attainment of apredetermined number of machine cycles, but of course a manual switchcan also be provided to enable the solenoid having arm 75 to beenergized selectively when desired. The entailed mechanism can beconveniently added to an existing machine, since the operable masterreleasing parts for releasing the master clamps in such a machine aresorelated as to be neatly nested substantially in the same planeadjacent one of the frame plates of the machine. The stripping action ispositive and a forced ejection is used, but even so, stripping andejection is accomplished without damaging the master. The ejecting unitcan be separably attached to an existing machine, and the arrangement inthis unit is such that cleaning of the ejector rollers can be easilyaccomplished.

It was mentioned that the form rollers and 191 are to be moved slightlyaway from the master cylinder during stripping of the master. Thismovement is only about 0.025 inch, sufiicient to prevent the master fromwrapping around the lower form roller while permitting some lfOI'C- ingaction of the lower form roller on the master being stripped, suchforcing action being merely that due to a slight contact between thetacky form roller and the tacky image on the master as distinguishedfrom a definite squeeze. In any event, the form rollers are to be raisedjust prior to the opening of the clamps which hold the master on themaster cylinder. This can be accomplished automatically in accordancewith the disclosure in co-pending application, Serial No. 2,546, filedJanuary 14, 1960; or, where only manual controls are "afforded, it canbe done by turning the conventional eccentric mounts for the formrollers just prior to manually energizing the solenoid having arm 75associated therewith.

Hence, while a preferred embodiment of the present invention has beenillustrated and described this is capable of variation and modification,and we therefore do not wish to be limited to the precise details setforth, but desire to avail ourselves of such changes and alterations asfall within the purview of the following claims.

We claimr c 11. In an offset-set printing machine wherein a master is tobe held on a rotatable master cylinder by a releasable clamp,'oscillatable stripper mean-s adjacent the master cylinder and normallydisposed in a position free of the path of the master, means to releasethe clamp, a cam for controlling the releasing means and normallydisposed in an ineffective position, means for shifting the cam t0 aneffective position after a predetermined number of prints have beenmade, means under control of said cam in its effective position topermit shifting of the stripper means into the path of the unclampedmaster to strip the unclamped master from the master cylinder, and a camrotatable with the master cylinder to control oscillation of thestripper means between the eifective and ineifective position thereof.

2. In an off-set printing machine wherein a master is to be held on arotatable master cylinder by a releasable clamp, oscillatable strippermeans adjacent the master cylinder and normally disposed in anineffective position free of the path of the master, means including acam follower to release the clamp, a shiftable cam shiftable to aneiieotive position to be engaged by said cam follower for controllingthe releasing means, said cam being normally in an ineffective position,means for shifting the cam to its effective position after apredetermined number of prints have been made, stripper releasing meansunder control of said cam in its inelfective position maintaining saidstripper means in ineffective position and permitting movement of thestripper means to an effective position when said cam shifts to itseifective position, and a timing cam rotatable with said master cylinderto time operation of the stripper means to be-effective after the masterhas been released.

3. In a cyclically operable off-set printing machine wherein a master isto be held on a rotatable master cylinder by a releasable clampincluding a spring biased plunger, oscillatable stripper means adjacentthe master cylinder and normally disposed in an ineffective positionfree of the path of the master, clamp releasing means to exert a clampopening force on said plunger to release the clamp and including a camfollower, a cam in a predetermined plane for controlling the clampreleasing means and normally in an ineffective position free of the pathof the follower, means substantially in said plane for shifting the camto its effective position into the path of said follower after apredetermined number of machine cycles, means under control of said camin its ineffective position to prevent shifting of the stripper meansand being released upon movement of the cam to its elfective position topermit movement of the stripper means into the path of the unclampedmaster to strip the unclamped master from the master cylinder, a camrotatable with the master cylinder to time oscillation of the strippermeans between the effective andineflective position thereof, guide meanscooperable with the stripper means to guide the stripped masteraway fromthe master cylinder, and driven feed rollers engageable with the leadingportion of the stripped master to exert a pulling force thereonincidental to ejecting the stripped master to a receiving statioiL' 4.In a cyclically operable off-set printing machine wherein a master is tobe held on a rotatable master cylinder by a releasable clamp including aspring biased plunger disposed in a gap in the master cylinder,oscillat-able stripper fingers carried on a rock shatt adjacent themaster cylinder and normally disposed in aposition free of the path ofthe master, said rock shaft having fixed thereto an arm with a camfollower thereon, spring means effective on said rock shaft to urge saidfingers toward said master cylinder, clamp releasing means to exert aclamp opening force on said plunger to release the clamp and includinganother cam follower, a cam disposed in a predetermined plane forcontrolling the clamp releasing means and normally in an ineffectiveposition free of the path of said followers, means substantially in saidplane for shifting the cam to its effective position into the path ofsaid other follower after a predetermined number of machine cycles,means substantially in said plane enabling said cam in its ineifectiveposition to apply a force to said rock shaft opposing said spring meansand being disabled from so acting in opposition when said cam is in 12its effective position to permit shifting of the stripper fingers intothe path of the unclamped master to strip the unclamped master from themaster cylinder, a cam rotatable with the master cylinder and engageablewith the firstnamed follower to control and time oscillation of thestripper fingers between the elfeotive and inefiective position thereof,an auxiliary ejector unit removably attached to the machine andincluding guide means having surfaces opposite related guide surfaces ofthe stripper fingers to guide the stripped master away from the mastercylinder, said auxiliary unit including driven feed rollers having :abight in position to receive the leading edge of the stripped mastermoving away from the master cylinder, and said auxiliary unit includinga receiving tray in position to receive the master advanced by said feedrollers.

5. In a cyclically operable ofl-set printing machine wherein a usedmaster is to be stripped from the master cylinder by stripper fingersrendered active automatically as an incident to completion of apredetermined number of machine cycles, a main frame supporting saidcylinder, an ejector unit including a pair of rigidly interconnectedside plates, manually releasable means on said ejector unit forreleasably attaching said unit to the main frame of the machine, a pairof spaced shafts rotatably supported between the side plates andrespectively provided with feed rollers, a guide plate for the strippedmaster and located on one side of said feed rollers and adapted to guidethe stripped master into the bight thereof, a receiving tray on theother side of the feed rollers to receive a master ejected by said feedrollers, and spaced guide fingers spaced above said guide plate andopposite said stripper fingers and defining therewith a narrowpassageway leading from the master cylinder to the feed rollers.

6. In an oil-set printing machine wherein a used master is to bestripped from the master cylinder automatically as an incident tocompletion of a predetermined number of machine cycles, a main framesupporting said cylinder, an ejector unit including a pair of rigidlyinterconnected side plates, means on said unit enabling the same to beremovably attached to the main frame of the machine, a pair of spacedshafts rotatably supported between the side plates and respectivelyprovided with feed rollers, a guide plate for the stripped master on oneside of said feedrollers and adapted to guide the stripped master intothe bight thereof, a receiving tray on the other side of the feedrollers to receive a master ejected by said feed rollers, horizontallyspaced guide fingers arranged above said guide plate and definingtherewith a narrow passageway leading from the master cylinder to thefeed rollers, and stripper fingers adjacent the master cylinder andhaving arcuate guide surfaces substantially aligned with said passagewayto guide a stripped master accurately thereinto.

7. In an ofi-set printing machine wherein a master is to be held on arotatable master cylinder by a releasable clamp, oscillatable strippermeans adjacent the master cylinder and normally disposed in a positionfree of the path of the master, means to release the clamp, a cam forcontrolling the releasing means and normally disposed in an ineffectiveposition, means for shifting the cam to an effective position after apredetermined number of prints have been made, means under control ofsaid cam in its effective position to permit shifting of the strippermeans into the path of the unclamped master to strip the unclampedmaster from the master cylinder, and timing means operative insynchronism with rotation of the master cylinder to control oscillationof the stripper means between the effective and ineifective positionthereof.

8. In a cyclically operable ofi-set printing machine wherein a usedmaster is to be stripped from the master cylinder by stripper fingersrendered active automatically as an incident to completion of apredetermined number of machine cycles, a main frame supporting saidcylinder, an ejector unit including a pair of rigidly interconnectedside plates, 21 pair of spaced shafts rotatably sup- 13 14 portedbetween the side plates and respectively provided References Cited inthe file of this patent with feed rollers, a guide plate for thestripped master and UNITED STATES PATENTS located on one side of saidfeed rollers and adapted to guide the stripped master into the bightthereof, a receiv- E: &'; ing tray 0n the other side of the feed rollersto receive a 5 Comm) 1940 master ejected by said feed rollers, andspaced guide fin- 2:331:351 seeley 1943 gers spaced above said guideplate and opposite said strip- 2 3 0 744 Ford July 31 945 per fingersand defining therewith a narrow passageway 2,758,539 Ritzerfeld et a1Aug. 14, 1956 leading from the master cylinder to the feed rollers.2,935,937 Rossetto et a1 May 10, 1960

1. IN AN OFFSET-SET PRINTING MACHINE WHEREIN A MASTER IS TO BE HELD ON AROTATABLE MASTER CYLINDER BY A RELEASABLE CLAMP, OSCILLATABLE STRIPPERMEANS ADJACENT THE MASTER CYLINDER AND NORMALLY DISPOSED IN A POSITIONFREE OF THE PATH OF THE MASTER, MEANS TO RELEASE THE CLAMP, A CAM FORCONTROLLING THE RELEASING MEANS AND NORMALLY DISPOSED IN AN INEFFECTIVEPOSITION, MEANS FOR SHIFTING THE CAM TO AN EFFECTIVE POSITION AFTER APREDETERMINED NUMBER OF PRINTS HAVE BEEN MADE, MEANS UNDER CONTROL OFSAID CAM IN ITS EFFECTIVE POSITION TO PERMIT SHIFTING OF THE STRIPPERMEANS INTO THE PATH OF THE UNCLAMPED MASTER TO STRIP THE UNCLAMPEDMASTER FROM THE MASTER CYLINDER, AND A CAM ROTATABLE WITH THE MASTERCYLINDER TO CONTROL OSCILLATION OF THE STRIPPER MEANS BETWEEN THEEFFECTIVE AND INEFFECTIVE POSITION THEREOF.